package com.chenxin.authority.common.servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

/**
 * Desc: 生成验证码的Servlet
 * User: ZhengCongChun
 * Date: 13-10-8
 * Time: 下午4:32
 *
 * @Version 1.0
 */
public class AuthCodeServlet extends HttpServlet {
    //设置字体
    private Font font = new Font("Times New Roman", Font.BOLD, 17);

    public void init() throws ServletException {
        super.init();
    }

    /**
     * 验证码图片的颜色
     * @param frontColor 前景色
     * @param backgroundColor 背景色
     * @return
     */
    Color getRandColor(int frontColor, int backgroundColor) {
        Random random = new Random();
        if (frontColor > 255) frontColor = 255;
        if (backgroundColor > 255) backgroundColor = 255;

        int red = frontColor + random.nextInt(backgroundColor - frontColor);
        int green = frontColor + random.nextInt(backgroundColor - frontColor);
        int blue = frontColor + random.nextInt(backgroundColor - frontColor);

        return new Color(red, green, blue);
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //表明生成的响应是图片
        response.setContentType("image/jpeg");

        int width = 100, height = 18;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(1, 1, width - 1, height - 1);
        g.setColor(new Color(102, 102, 102));
        g.drawRect(0, 0, width - 1, height - 1);
        g.setFont(font);

        g.setColor(getRandColor(160, 200));

        //画随机线
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width - 1);
            int y = random.nextInt(height - 1);
            int xl = random.nextInt(6) + 1;
            int yl = random.nextInt(12) + 1;
            g.drawLine(x, y, x + xl, y + yl);
        }

        //从另一方向画随机线
        for (int i = 0; i < 70; i++) {
            int x = random.nextInt(width - 1);
            int y = random.nextInt(height - 1);
            int xl = random.nextInt(12) + 1;
            int yl = random.nextInt(6) + 1;
            g.drawLine(x, y, x - xl, y - yl);
        }

        //生成随机数,并将随机数字转换为字母
        String authCode = "";
        for (int i = 0; i < 6; i++) {
            int itmp = random.nextInt(26) + 65;
            char ctmp = (char) itmp;
            authCode += String.valueOf(ctmp);
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(String.valueOf(ctmp), 15 * i + 10, 16);
        }

        //设置成session，在登陆的Servlet上验证
        HttpSession session = request.getSession(true);
        session.setAttribute("authCode", authCode);

        g.dispose();
        ImageIO.write(image, "JPEG", response.getOutputStream());
    }

    public void destroy() {

    }
}
